DCI: LS1.C Organization for Matter and Energy Flow in Organisms –
Plants acquire their material for growth chiefly from air and water.
PE: 5-LS1-1 Support an argument that plants get the materials they
need for growth chiefly from air and water.
[Clarification
Statement: Emphasis is on the idea that plant matter comes mostly from air and
water, not from the soil.]
The ideas we see in this standard are:
- The physical matter making up plants comes primarily from materials the plants obtain through the air and from water. (as the inputs of photosynthesis are carbon dioxide and water).
Although this is not a photosynthesis standard, it is laying the groundwork for later standards which concentrate on the inputs and outputs of photosynthesis. We cannot ask specific questions about the chemical process of photosynthesis, but we do need to find ways to point to the idea that the matter which plants are made of is transformed from matter that came from outside of the plant. Many students will be operating under the misconception that plants grow because they are given nutrients such as fertilizers and that the materials needed for growth come from soil. These concepts are hard to grasp, as the idea that the matter instead comes from the air is hard to grasp.
Students should not be expected to name the gas carbon dioxide as an input of photosynthesis, rather, they just need to know, vaguely speaking, that matter in the air is used for growth in plants.
Possible Question Starters:
-"Some of the materials plants need in order to grow come from - "
correct answer -the air
incorrect answer - the soil, other plants, etc.
-"Which of the following investigations would provide the best evidence that plants need water in order to grow?"
-correct answer - planting two of the same kind of plant in a similar environment, watering one plant every day and not watering the other plant.
-incorrect answer - planting two different types of plant in a similar environment, and watering them the same amount.
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